Controls: PLC, HMI, IPC

The layer everything else depends on. Platform selection, migration off obsolete controllers, code standards, and whether what gets installed is supportable after the integrator leaves.

Where this sits

This is ISA-95 Level 1-2. Naming the layer matters, because the most expensive mistakes in modernization come from solving a problem at the wrong level of the stack.

What we actually do here

• Assess what is installed, what version it is on, and what depends on it
• Decide what to modernize, in what order, and what to deliberately leave alone
• Write scope and acceptance criteria that a vendor cannot quietly reinterpret
• Review design and code before commissioning, not after
• Make sure the plant can support the result once the project team has gone

Platform position

Vendor-independent, but not opinion-neutral. When one platform is clearly better for a given situation, we will say which and why. When the honest answer is that the existing system is fine and the money is better spent elsewhere, that is the recommendation.